Unformatted text preview: aulic contribution is kept constant by increasing the HSI from 2.0 hp/in2 to 2.9 hp/in2. The additional
ROP can be explained by the improved drilling efficiency. Less energy is wasted re-working on the crushed rock material not
properly removed when the bit hydraulic contribution decreases when only the mechanical energy is increased.
DSE with Field Data
Field data was used to calculate DSE, using Eq. 8, in order to identify inefficient drilling conditions. Initially, DSE and ROP
were both plotted against depth to identify any particular pattern. Then the drilling parameters WOB, RPM, Torque and HSI
were also plotted vs. depth to explain the observed pattern (Field cases No. 1 and 2). Furthermore, DSE was calculated using
surface and downhole data and plotted vs. depth (Field case No. 3). The results were used to compare DSE with the rock
compressive strength (UCS and CCS).
Field Case No. 1: Bit Balling
On this well, the 17-1/2 in. section is drilled with a 9.0 lb/gal water based mud across a shale formation. One bit was used to
drill from 2,200 ft to 5,300 ft. At this depth, the bit is pulled ou...
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This note was uploaded on 01/31/2014 for the course MOGE 9114 taught by Professor Thomod during the Spring '13 term at Memorial University.
- Spring '13